Safety latch-mine skip



Jan. 26,- 1932. R. J. WILLIAMS SAFETY LATCH MINE SKIP JLZ Filed Sept.27, 1928 banjo/1- We J wzzmma,

Patented Jan. 26, 1932 UNITED STATES Brennan J. WILLIAMS, or VIRGINIA,MINNESOTA sArETY LATCH-MINE (SK-I1 Application filed September 27, 1928.Serial No. 308,679.

This invention relates to safety appliances and is illustrated herein asembodied in a device for use in connection with elevator hoists toprevent falling ,of the car, orlift, upon accidental severance of thehoisting cable 7 In the operation ofvarious elevator hoists, such,for'example, as those employed in mines, the controlling apparatus mayfor some reason or other fail to operate properly with the result thatthe liftor' skip, as theyare commonly termed in the mining artdoes notstop when it reaches the limit of its upward travel, but continues .tobe pulled vertically until it overtravels the guides upon which it ismounted, and, jams against theframe work of the shaft. Notwithstandingthe fact thatthe skip is in such a condition, the hoisting apparatus maystill continue to operate, putting more and more tension on the hoistingcable until the latter tears apart and the skip drops downwardly intothe mineshaft wrecking itself at the bottom, with apossibility of doing'greatdamage and possiblycausingloss of life. 1

This undesirable manner of operation on the part of the hoist iscommonly termed an overwind, and it'is an important object of thepresent invention to provide an improved device or mechanism forpreventing a skip or hoist fromfalling'if the hoistingcable is partedby'reason of an overwind. It is further anobject of the inventiontoprovide a device of this character thatiis simple in design andconstruction and relatively inexpensive to manufacture-and to-install.

A feature of the'invention which leads-to the accomplishment of therecited objects consists in providing'adevice that is normallystationary, but is operable upon contact with the hoist to move into aposition in which it prevents the hoist from'falling downwardly in theshaft. It is to be appreciated, of course, that the most accurate mannerin which the operation of the safety mechanism could be timed is by itsengage mentwith the hoist, or skip, and according- 1y, it is proposed tomount the safety mechanism at the top of the shaft immediately adjacentto the limit oftheupward travel of the hoist, in which condition itremains normally inoperative and out ofthe Way, but will, upon beingengaged by the hoist, move nto a position to prevent the latterfromfall- Still another feature of the invention consists in constructingthe safety device in such a manner that when'it has once operated toprevent the skip from falling, it must be reset to reassume an operativeposition before Other objects and features of the invention will becomeapparent from a reading of the following specification in the light ofthe accompanying drawing in which there is shown an elevator hoistsuitable for mining use and equipped with a safety mechanism of theimproved character.

As shown in the drawing, the elevatorhoist comprises, generallyspeaking, a plurality of containers, 10, 12, which are known by suchterms as skips, cars, buckets, hoists, etc.,

arranged for vertical movement between guideways 14c andldrespectively.A sloping bin '18 is arranged to receive material from the containers10, 12 and is provided withla track 20, running beneath the bin, inorder 1 that dump cars 22may berolled into a position beneath the outletof the bin to receive materials therefrom. The skips 10 and 12 areprovided upon opposite sides with outwardly projecting lugs 2 k, whichare arranged to ride in grooves formed in the guideways 14, 16, untilthe point 26 is reached, whereupon they move inwardly through theguidewa-ys 28, causing the top of the bucket to swing downwardly as thebottom of the bucket is raised. It is during such movement, of course,that the dumping operation betweenthe bucket and the bin takes place.

The mechanism for hoisting the skips 10 and 12, comprises, asillustrated, a hoisting apparatus 30 that is provided with meansnormally adapted to prevent overwinding of hoisting cables 32 which leadover sheaves 34 and connect, by means of clevises, with the upper crossbar of rectangular bails 36, which carry the skips 10 and 12.

From an inspection of the drawing, it will be seen that if the apparatusshould continue to hoist after the skip has reached the limit of itsupward travel, then the clevis in the loop end would bind upon and tendto move upwardly in the groove of the sheave 34 until the tensionbrought about by the bail 36 jamming on the guideways 16, would overcomethe tension applied to the hoisting apparatus 30, whereupon the hoistingcable would sever and the bail 86 and container 12 would crashdownwardly to the bottom of the shaft where it would wreck itself and,in great likelihood, cause considerable damage.

In order to prevent the skip from falling in the event that an overwindtakes place, there is provided a safety device or mechanism which isarranged for movement between an inoperative out of the way posi tion,and an operative skip engaging pos1- tion. As shown in the drawing, arotatable shaft 40 is mounted at the top of the shaftway or skip-way andis provided with a plurality of arms 42 which extend outwardly in aposition to overlie the path of movement of the skips 10 and 12, wherebythe outwardly extending arms are engaged by the skips if the latterexceed their respective limits of upward travel, and cause rotation ofthe shaft 40. Integral arms 44 extend rearwardly from the opposite endsof the shaft 40 and pivotally connect with link connecting rods 46which, at their lower extremities pivotally connected to safety latchmembers 48. A supplemental integral arm 50 extends centrally from theshaft 40 and is connected to a plurality of links 52, which arepivotally connected with uniformly operating safety latch members 54, itbeing observed that both of the safety latches 48 and the latches 54 arepivotally mounted at one extremity upon the frame work of the elevatorshaft.

In discussing the operation of the safety device shown in the drawing,it is requested that the reader first turn his attention to the skip 10,which is shown in a lower position than the skip 12, and picture thetravel of the skip 10 as it moves upwardly in the shaftway. The arm 42extending from the shaft 40 overlies the upper member of the bail 36,which carries the skip 10 and if the hoisting apparatus does not operateto stop the upward movement of the bail upon the skip 10 moving into adumping position, the bail will engage the overlying lever 42 and moveit upwardly, thereby rotating the shaft, thrusting the lever 46downwardly, and moving the safety latch 48 into a position in which itunderlies the bail 36, in the manner shown in the drawing in connectionwith the skip 12, whereby it is impossible for the skip to fall in theevent that the cable severs.

When the safety apparatus has once been operated and the latch 48 isunderlying the hail of the skip, a lever 60 extending from the oppositeends of the shaft 40 in directions opposite to the levers 44 may beoperated manually to movethe safety latch into an inoperative positionin which the skip is free to descend. It is to be noted in thisconnection that such words as skip, hoist, car, etc., are intended toinclude both the bail and the container mounted within the bail and notmerely the container alone.

From so much of the description as appears above, it will be understoodthat normally the safety latch members 48 occupy an out of the wayposition which means, of course, that the contact members 42 will occupya position in which they overlie the skip-ways, whereby the skips 10 and12, striking the members 42, will cause the latch members to be movedoutwardly into engagement with the skips. An important considerationresides in the fact that if by chance the safety latch members 48 shouldbe disposed in an outward, operative position while the skips arebeneath them, they will, upon being engaged by the upper edge of theskips, be swung into an inoperative position and the contacting levers42 will accordingly be moved into an operative position, the result ofthis being that the safety latch is bound to operate at all times, forif it occupies an inoperative position, the skip itself moves it into anoperative position before the limit of upward movement of the skip hasbeen reached and thereafter the safety latch is properly set foroperation. It is also to be observed that when the latch is moved froman operative position such as that shown in the drawing to aninoperative position in which it will be disposed out of the path of theskip, the contacting arms 42 must perforce be moved downwardly into aposition to overlie the skip-ways. Thus, in releasing the skips, thesafety devices are simultaneously reset for a subsequent operation.

While the invention has been discussed herein, with particular referenceto mining hoists, it is to be understood that it may be used inconnection with elevators and hoists of practically every kind anddescription, and it is likewise to be understood that the inventioncontemplates the incorporation therein of modifications and changes suchas will from time to time appear to those skilled in the art.

Having thus described my invention, what I claim as new and desire tosecure by United States Letters Patent is:

1. An elevator hoist having, in combination, a vertically extendingshaft, a lift mounted within the shaft, means for operating the lift,and safety means for preventing the lift from falling upon failure ofthe operating means, said safety means comprising a pivoted leveradapted to be engaged by the lift, and a pivoted lever adapted to engagea projection carried by the lift, the members being so constructed andarranged that movement imparted'to either of the levers results inmovement being imparted to the other.

2. An elevator hoist having, in combination, a vertically extendingshaft, a lift mounted within the shaft, a cable operable to impartmovement to the lift, a rocker arm located at the top of the shaft andprovided with a lever arranged to extend laterally into the shaft forthe purpose of being engaged by the lift to oscillate the rocker arm, asecond rocker arm located a substantial distance below the first arm andprovided with a lever arranged to extend laterally into the shaftrestrainingly to engage the lift, a connection extending between the tworocker arms and so arranged that movement of one of the members into aposition extending laterally into the shaft causes retraction of theremaining member out of the shaft, and a lever carried by the firstnamed rocker arm for imparting movement thereto.

Signed at Virginia, Minnesota, this 17th day of September, 1928.

RICHARD J. WILLIAMS.

